Liquid crystal display device

ABSTRACT

A liquid crystal display device comprises first and second substrates, an alignment layer including a pyranose polymer or a furanose polymer on at least one of the first and second substrates, and a liquid crystal layer between the first and second substrates. The liquid crystal display device is characterized by excellent thermostability, superior anchoring energy and uniform alignment of the liquid crystal achieved in a reduced treatment time without creating any flowing effect in the liquid crystal.

This application claims the benefit of Korean Application No.1997-61755, filed Nov. 21, 1997, and No. 1998-18189, filed May 20, 1998,which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device, andmore particularly to a liquid crystal display device having aphoto-alignment layer.

2. Description of the Related Art

It is generally known that a liquid crystal consists of anisotropicmolecules. The average direction of the long axes of liquid crystalmolecules is called the director of the liquid crystal. The directordistribution in a liquid crystal is determined by the anchoring energyon a substrate, and is characterized by a director corresponding to aminimum of the surface energy of the liquid crystal and the anchoringenergy. The director is rearranged by an electric field generated duringoperation of a liquid crystal display device (LCD). An LCD comprises twoopposed substrates having liquid crystal therebetween.

In general, to obtain uniform brightness and a high contrast ratio, itis necessary to align the liquid crystal molecules uniformly in theliquid crystal cell. Several techniques have been proposed usingpolymers to obtain single or mono-domain homogeneous alignment of liquidcrystals. Particularly, it is known that polyimide or polysiloxane-basedmaterials have high quality and good thermostability. The most commontechnique employed as an alignment method to obtain a mono-domain liquidcrystal cell involves forming microgrooves on the surface of thealignment polymer, which provides strong anchoring and stable alignment.In the above-mentioned technique, known as the rubbing method, asubstrate coated with an alignment polymer is rubbed with a cloth. Therubbing method is a rapid method which can be applied to large scaleLCDs, and thus is widely used in the industry.

The rubbing method, however, has several serious drawbacks. Because theshape of the microgrooves formed on the alignment layer depends on therubbing cloth and rubbing intensity, the resulting alignment of theliquid crystal is often heterogeneous, causing phase distortion andlight scattering. Further, an electrostatic discharge (ESD) generated byrubbing of the polymer surface further generates dust contamination inan active matrix LCD panel, decreasing production yield and damaging thesubstrate.

In order to solve these problems, a photo-alignment method has beenproposed using a polarized ultraviolet light irradiated onto aphotosensitive polymer to photo-polymerize the polymer (A. Dyadyusha, V.Kozenkov et al., Ukr. Fiz. Zhurn., 36 (1991) 1059; W. M. Gibbons et al.,Nature, 351 (1991) 49; M. Schadt et al., Jpn. J. Appl. Phys., 31 (1992)2155; T. Ya. Marusii & Yu. A. Reznikov, Mol. Mat., 3 (1993) 161; EP0525478; and U.S. Pat. No. 5,538,823— a polyvinyl-fluoro cinnamatepatent). The alignment capability of the photosensitive polymer isdetermined by the anisotropy of the photosensitive polymer, which isinduced by ultraviolet light irradiation.

In the photo-alignment method, an alignment layer is given an alignmentdirection by irradiating a substrate coated with a photo-alignmentmaterial with a linearly polarized UV light. The photo-alignment layercomprises a polyvinyl cinnamate-based (PVCN) polymer, and as linearlypolarized UV light is irradiated, the polymer photo-polymerizes throughcross-linking. Cross-linking is generated among the polymers by the UVlight energy.

In terms of the direction of the photo-polymers, the alignment directionof the photo-alignment layer has a specific direction in relation to thepolymerization direction of the linearly polarized UV light. Thealignment direction of the photo-alignment layer is determined by thedirection of the photo-polymers. The pretilt angle of thephoto-alignment layer is determined by the incident direction and theirradiating energy of the irradiated UV light. That is to say, thepretilt angle direction and the pretilt angle of the photo-alignmentlayer are determined by the polarized direction and the irradiatingenergy of the irradiated UV light.

With regard to photo-alignment, a polarizer is rotated in an arbitraryangle on each domain of the LCD. Then, in response to irradiating UVlight, the polarization direction is changed, whereby a multi-domain LCDcell is achieved with multiple domains having different alignmentdirections in relation to each other.

The photo-alignment method, however, has several drawbacks. For example,it is impossible to apply on a wide scope. Most importantly, lowphoto-sensitivity of the photo-alignment material results in reductionof anisotropy and thermostability.

UV light irradiation takes a long time using conventional techniques,from approximately 5 to as long as 10 minutes. Low photo-sensitivity andsmall anisotropy make the anchoring energy of the final photo-alignmentlayer weak. Moreover, when the liquid crystal is injected into the LCD,it is required that the injection be made at a high temperature. Lowthermostability induces a flowing effect on the substrates, which can beobserved as a ripple pattern in the liquid crystal upon injectionbetween the substrates. Finally, disclination owing to the uniformalignment of liquid crystals remains as a problem to be solved.

SUMMARY OF THE PREFERRED EMBODIMENTS

Accordingly, the present invention is directed to a LCD thatsubstantially obviates one or more of the problems due to limitationsand disadvantages of the related art.

An object of the present invention is to provide an LCD having goodthermostability and photo-sensitivity.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, theliquid crystal display device of the present invention comprises firstand second substrates, an alignment layer including a pyranose or afuranose polymer on at least the first substrate, and a liquid crystallayer between the first and second substrates.

The liquid crystal display device of the present invention preferablycomprises a second alignment layer on the second substrate. The secondalignment layer includes a material selected from the group consistingof a pyranose polymer, a furanose polymer, polyvinyl cinnamate,polysiloxane cinnamate, polyvinyl alcohol, polyamide, polyimide,polyamic acid and silicone dioxide.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 illustrates the synthesis of a cellulose cinnamate according toan embodiment of the present invention;

FIG. 2 schematically illustrates an embodiment of a system of lightirradiation of a photo-alignment layer in accordance with the presentinvention; and

FIG. 3 is a sectional view of an embodiment of a liquid crystal displaydevice according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

A liquid crystal display device of the present invention will now beexplained in detail in conjunction with the accompanying drawings.

According to an embodiment of the present invention, in order to enhancethe sensitivity of a photo-alignment layer for a liquid crystal deviceand obtain thermostable anchoring of the liquid crystal, a cellulosecinnamate (CelCN) is used as the photo-alignment material. Severaldifferent forms of CelCN suitable for use in the present invention areobtained as derivatives of cellulose or cellulose acetate and cinnamoylchloride having various substitution ratios.

Pyranose polymers and furanose polymers are particularly preferred foruse as the cellulose cinnamates of the present invention.

Pyranose polymers suitable for use in the present invention arecharacterized by the following chemical formula:

wherein m is 10 to 10,000;

R is at least one member selected from the group consisting of

and

n is 1 to 10;

X₁ and X₂ are each selected from the group consisting of hydrogen,fluorine, chlorine, methyl and methoxy;

k is 0 to 1; and

Y is selected from the group consisting of hydrogen, fluorine, chlorine,cyano, trifluoromethyl, trifluoromethoxy, C_(n′)H_(2n′+1) andOC_(n′)H_(2n′+1), wherein n′ is 1 to 10.

In a particularly preferred form of the invention, the alignment layeris characterized by 0 to 2

constituents per glucopyranose ring, wherein n is 1 to 10.

As is well-known in the art, the four possible glucopyranoseconformations and the four possible galactopyranose conformations, eachof which conformations is within the scope of the terms cellulose andcellulose acetate as used in the present invention, are illustrated bythe following formulas:

FIG. 1 shows the synthesis of a cellulose cinnamate according to anembodiment of the present invention. A cinnamic acid is first preparedby reacting a benzaldehyde with malonic acid in pyridine and piperidine.The cinnamic acid is then reacted with thionyl chloride to produce acinnamoyl chloride derivative. The CelCN is finally synthesized byreacting cellulose, or cellulose acetate, with the cinnamoyl chloridederivative in an inert solvent (such as chloroform, nitrobenzene,chlorobenzene, or the like). The reaction mixture is diluted withmethanol, filtered, dried in a vacuum, and milled by a vibrating mill,whereupon the CelCN is obtained.

A process of forming an alignment layer according to an embodiment ofthe present invention comprises the following three steps.

First, a polymer solution is prepared using chloroform (CHCl₃)as asolvent. The concentration of the polymer determines the ultimatethickness of the alignment layer on the LCD substrates. To form a filmhaving a thickness of approximately 1 μm, a CelCN solution of 10 g/l isselected for coating the substrate.

Second, a drop of the CelCN solution is placed in the center of thesubstrate using a measuring pipette, followed by spin-coating whilecentrifuging at a rotation speed of 3000 rpm for 30 seconds. Theproduced film is immediately prebaked at 180° C. for 1 hour.

Third, the initially isotropic polymer film is irradiated with polarizedUV light having a wavelength λ below 365 nm to render it anisotropic,with either a positive or a negative dielectric. The irradiation time ismore than 5 seconds, and the intensity of UV light is about 5 mW/cm^(2.)

FIG. 2 illustrates a scheme of light irradiation of a photo-alignmentlayer of the present invention.

As shown in FIG. 2, an embodiment of the light irradiating procedureutilizes a substrate 100, a photo-alignment layer 50 including a CelCNon substrate 100, a lamp 10 for irradiating UV light overphoto-alignment layer 50, and a polarizer 30 for polarizing the lightirradiated from lamp 10.

Lamp 10 is a Halogen (Hg) lamp. Light having an average power of 500 Wis transmitted from a lens of the halogen lamp, polarized by polarizer30, and irradiated onto photo-alignment layer 50 at a power of 5 mW/cm²for about 0.5 to about 180 seconds, more preferably about 0.5 to about60 seconds, and most preferably about 3 to about 60 seconds.

The alignment obtained from the CelCN polymers of the present inventionhas a stronger anchoring energy compared with the alignment obtainedfrom conventional photo-alignment materials. The values of the anchoringenergy of CelCN versus typical prior art photo-alignment materials,including polyvinyl fluorocinnamate (PVCN-F) and polysiloxane cinnamate(PSCN), have been measured. The results are shown in the following TABLE1:

TABLE 1 Irradiation Time Anchoring Energy Material (seconds) (erg/cm²)cellulose 4-  5 greater than 10⁻² fluorocinnamate cellulose 4- 300greater than 10⁻² fluorocinnamate polyvinyl-  5 3 × 10⁻⁴ fluorocinnamatepolyvinyl- 300 10⁻² fluorocinnamate polysiloxane-  5 bad alignment;cinnamate measuring failure polysiloxane- 300 5 × 10⁻³ cinnamate

To estimate the thermostability of the CelCN, the quality of thealignment layer was checked using an electro-optical technique.Electro-optical response, in terms of cell transparency ratio betweencrossed and parallel polarizers, anchoring energy and surface density ofthe alignment layer were each measured in a twisted nematic (TN) cellcontaining samples of the CelCN layers. The cell was heated to about120° C. and kept at this temperature for 4 hours. After cooling thesamples to room temperature, it was revealed that the performancecharacteristics were maintained unchangeably.

Among its other advantages, the present invention thus significantlyreduces UV irradiation time. Whereas prior art photo-alignmenttechniques involved UV irradiation for anywhere from 5 to 10 minutes,the present invention provides a method which successfully achievesphoto-alignment using UV irradiation in anywhere from about 0.5 secondsto one minute.

Preferred embodiments of the present invention will now be described infurther detail. It should be understood that these examples are intendedto be illustrative only and that the present invention is not limited tothe conditions, materials or devices recited therein.

EXAMPLE 1 Synthesis of 4-fluorocinnamic acid

A mixture of 0.1 mol 4-fluorobenzaldehyde, 0.15 mol malonic acid, and0.1 ml piperidine in 30 ml pyridine is boiled for 10 hours, cooled, andtreated with 150 ml HCl having a 10% concentration. The precipitate isfiltered and crystallized with ethanol. The yield of 4-fluorocinnamicacid is 68% and the melting point is 211° C.

The following compounds are synthesized in a similar manner:

2-fluoro cinnamic acid;

3-fluoro cinnamic acid;

3-chloro cinnamic acid;

4-chloro cinnamic acid;

2-methyl cinnamic acid;

4-phenyl cinnamic acid;

4-methoxy cinnamic acid;

4-pentoxy cinnamic acid;

4-heptyloxy cinnamic acid;

4-nonyloxy cinnamic acid;

4-(4-pentoxyphenyl)cinnamic acid;

4-trifluoromethoxy cinnamic acid;

4-trifluoromethyl cinnamic acid;

4-pentyl cinnamic acid; and

4-methoxy-3-fluorocinnamic acid.

EXAMPLE 2 Synthesis of cellulose cinnamate

A mixture of 0.05 mol cinnamoyl chloride (prepared from a cinnamic acidproduced in Example 1, an excess of thionyl chloride, and catalyticquantities of dimethyl formamide), 0.01 mol cellulose, and 0.04 molpyridine in 20 ml nitrobenzene is heated for 24 hours at 120° C.,cooled, and diluted with methanol. The reaction product is filtered,washed with methanol and water, dried in a vacuum, and subsequentlymilled by a vibrating mill.

Pyranose polymers are produced in the above manner using each of thecinnamic acids produced in Example 1. The yield of cellulose cinnamateis approximately 65% to 92%. Thin layer chromatography (TLC) revealsthere is no cinnamic acid in the reaction products.

EXAMPLE 3 Synthesis of cellulose acetate cinnamate

A mixture of 0.03 mol cinnamoyl chloride (prepared from a cinnamic acidproduced in Example 1, an excess of thionyl chloride, and catalyticquantities of dimethyl formamide), 0.01 mol cellulose acetate, and 0.03mol pyridine in 20 ml chloroform is boiled for 24 hours, cooled, anddiluted with methanol. The reaction product is filtered, washed withmethanol and water, dried in a vacuum, and subsequently milled by avibrating mill.

Pyranose acetate polymers are produced in the above manner using each ofthe cinnamic acids produced in Example 1. The yield of cellulose acetatecinnamate is approximately 65% to 92%. Thin layer chromatography (TLC)confirms there is no cinnamic acid in the reaction products.

FIG. 3 is a sectional view of an embodiment of a liquid crystal displaydevice of the present invention.

As shown in FIG. 3, the LCD comprises first and second substrates 100and 101, respectively, a thin film transistor (TFT) 70 on firstsubstrate 100, a first alignment layer 50 formed entirely over TFT 70and first substrate 100, a second alignment layer 51 formed on secondsubstrate 101, and a liquid crystal layer 90 injected between first andsecond substrates 100 and 101.

First and/or second alignment layers 50, 51 include a pyranose orfuranose polymer, for example the CelCN shown in FIG. 1. The CelCNprovides good uniform alignment in a short irradiation time. Forexample, irradiation for as little as 0.5 seconds gives a stablealignment.

The pyranose and furanose polymers preferably comprise bothphoto-sensitive constituents and non-photo-sensitive constituents whichare composited in a specific ratio. The pyranose and furanose polymerscan be composited with only one constituent from each of photo-sensitiveand non-photo-sensitive constituents, or one or more differentphoto-sensitive and/or non-photo-sensitive constituents.

Suitable photo-sensitive constituents for use in the pyranose andfuranose polymers of the present invention include an array of cinnamoylderivatives, which can include substituents such as hydrogen, fluorine,chlorine, cyano, trifluoromethyl, trifluoromethoxy, C_(n′)H_(2n′+1),OC_(n′)H_(2n′+1), phenyl and C₆H₄OC_(n′)H_(2n ′+1), wherein n′ is 1 to10.

Suitable non-photo-sensitive constituents for use in the pyranose andfuranose polymers of the present invention include various esterderivatives, such as

wherein n is 1 to 10.

When UV light is irradiated onto the first and/or second alignmentlayers at least once, the alignment angle, the alignment directionthereof, the pretilt angle and the pretilt angle direction thereof aredetermined and alignment stability of the liquid crystal is achieved.

As the light used in the photo-alignment method, light in the UV rangeis preferable. It is not advantageous to use unpolarized light, linearlypolarized light, or partially polarized light.

Moreover, it is contemplated as within the scope of the presentinvention that only one substrate of the first and second substrates bephoto-aligned using the above-described method while the other substrateis not so treated. If both substrates are photo-aligned, it is withinthe scope of the invention that the other substrate be treated withpolyamide or polyimide as the alignment material and that the alignmentbe accomplished by prior art rubbing methods. It is also possible to usea photo-sensitive material such as polyvinyl cinnamate (PVCN) orpolysiloxane cinnamate (PSCN) as the alignment material for the othersubstrate and accomplish the alignment using photo-alignment methods.

As to the nature of liquid crystal layer 90, it is possible to align thelong axes of the liquid crystal molecules parallel with the first andsecond substrates to produce a homogeneous alignment. It is alsopossible to align the long axes of the liquid crystal moleculesperpendicular to the first and second substrates to achieve ahomeotropic alignment. Moreover, it is possible to align the long axesof the liquid crystal molecules with a specific predetermined angle inrelation to the substrates, with a tilted alignment in relation to thesubstrates, with a twisted alignment in relation to the substrates, orin an alignment parallel to one substrate and perpendicular to the othersubstrate to provide a hybrid homogeneous-homeotropic alignment. It isthus essentially within the scope of the present invention to apply anymode of alignment of the liquid crystal molecules in relation to thesubstrates as may be desired, such choices being apparent to one ofordinary skill in the art.

According to the present invention, the first and/or second alignmentlayers can be divided into two or more domains by creating differentdirectional alignments of the liquid crystal molecules on each domain inrelation to the direction of the substrates. Accordingly, a multi-domainLCD such as a 2-domain LCD, a 4-domain LCD, and so on can be obtained,wherein the liquid crystal molecules in each domain are drivendifferently.

An LCD made in accordance with the present invention is characterized byexcellent thermostability. It is thus possible to inject the liquidcrystal into the liquid crystal device at room temperature whilepreventing and avoiding any flowing effect from generating, as occurs inconventional techniques. Furthermore, the photo-alignment layer of thepresent invention possesses excellent photosensitivity, adhesion, andstrong anchoring energy. As a result, it is possible to align the liquidcrystal effectively and increase alignment stability of the liquidcrystal.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the liquid crystal displaydevice of the present invention without departing from the spirit orscope of the invention. Thus, it is intended that the present inventioncover the modifications and variations of this invention provided theycome within the scope of the appended claims and their equivalents.

What is claimed is:
 1. A first liquid crystal display device comprising:first and second substrates; a first alignment layer including apyranose polymer and at least one photo sensitive constituent on saidfirst substrate; and a liquid crystal layer between said first andsecond substrates.
 2. The liquid crystal display device according toclaim 1, further comprising a second alignment layer on said secondsubstrate.
 3. The liquid crystal display device according to claim 2,wherein said second alignment layer includes a material selected fromthe group consisting of a pyranose polymer, a furanose polymer,polyvinyl cinnamate, polysiloxane cinnamate, polyvinyl alcohol,polyamide, polyimide, polyamic acid and silicone dioxide.
 4. The liquidcrystal display device according to claim 1, wherein liquid crystal insaid liquid crystal layer has a positive dielectric anisotropy.
 5. Theliquid crystal display device according to claim 1, wherein liquidcrystal in said liquid crystal layer has a negative dielectricanisotropy.
 6. The liquid crystal display device according to claim 1,wherein at least one of said first and second alignment layers isdivided into at least two domains, for driving liquid crystal moleculesin said liquid crystal layer differently on each domain.
 7. The liquidcrystal display device according to claim 1, wherein liquid crystalmolecules in said liquid crystal layer align homogeneously in relationto at least one of said first and second substrates.
 8. The liquidcrystal display device according to claim 1, wherein liquid crystalmolecules in said liquid crystal layer align homeotropically in relationto at least one of said first and second substrates.
 9. The liquidcrystal display device according to claim 1, wherein liquid crystalmolecules in said liquid crystal layer are arranged in tilted alignmentin relation to at least one of said first and second substrates.
 10. Theliquid crystal display device according to claim 1, wherein liquidcrystal molecules in said liquid crystal layer are arranged in twistedalignment in relation to at least one of said first and secondsubstrates.
 11. The liquid crystal display device according to claim 1,wherein liquid crystal molecules in said liquid crystal layer alignhomogeneously in relation to one substrate of said first and secondsubstrates and align homeotropically in relation to another substrate ofsaid first and second substrates.
 12. The liquid crystal display deviceaccording to claim 1, wherein said pyranose polymer includes at leastone non-photo-sensitive constituent.
 13. The liquid crystal displaydevice according to claim 1, wherein said photo-sensitive constituent isa cinnamoyl derivative.
 14. The liquid crystal display device accordingto claim 13, wherein said cinnamoyl derivative includes at least onemember selected from the group consisting of hydrogen, fluorine,chlorine, cyano, trifluoromethyl, trifluoromethoxy, C_(n)H_(2n+1),OC_(n)H_(2n+1), phenyl and C₆H₄OC_(n)H_(2n+1), wherein n is 1 to
 10. 15.The liquid crystal display device according to claim 12, wherein saidnon-photo-sensitive constituent is an ester derivative.
 16. The liquidcrystal display device according to claim 15, wherein said esterderivative is

 and n is 1 to
 10. 17. The liquid crystal display device according toclaim 1, wherein said pyranose polymer is

wherein m is 10 to 10,000; R is selected from the group consisting of

 and

n is 1 to 10; X₁ and X₂ are each selected from the group consisting ofhydrogen, fluorine, chlorine, methyl and methoxy; k is 0 to 1; and Y isselected from the group consisting of hydrogen, fluorine, chlorine,cyano, trifluoromethyl, trifluoromethoxy, C_(n′)H_(2n′+1), andOC_(n′)H_(2n′+1), wherein n′ is 1 to
 10. 18. The liquid crystal displaydevice according to claim 17, wherein said pyranose polymer has 0 to 2

constituents per one glucopyranose ring, and n is 1 to
 10. 19. Theliquid crystal display device according to claim 1, wherein saidpyranose polymer is cellulose 4-fluorocinnamate.
 20. A liquid crystaldisplay device, comprising: first and second substrates; a firstalignment layer including furanose polymer on said first substrate; anda liquid crystal layer between said first and second substrates.
 21. Theliquid crystal display device according to claim 20, further comprisinga second alignment layer on said second substrate.
 22. The liquidcrystal display device according to claim 21, wherein said secondalignment layer includes a material selected from the group consistingof pyranose polymer, furanose polymer, polyvinylcinnamate,polysiloxanecinnamate, polyvinylalcohol, polyamide, polyimide, polyamicacid, and silicondioxide.
 23. The liquid crystal display deviceaccording to claim 20, wherein liquid crystal in said liquid crystallayer has a positive dielectric anisotropy.
 24. The liquid crystaldisplay device according to claim 20, wherein liquid crystal in saidliquid crystal layer has a negative dielectric anisotropy.
 25. Theliquid crystal display device according to claim 20, wherein said firstor second alignment layer is divided into at least two domains, to drivedifferently liquid crystal molecules in said liquid crystal layer oneach domain.
 26. The liquid crystal display device according to claim20, wherein liquid crystal molecules in said liquid crystal layer alignhomogeneous against said first or second substrate.
 27. The liquidcrystal display device according to claim 20, wherein liquid crystalmolecules in said liquid crystal layer align homeotropic against saidfirst or second substrate.
 28. The liquid crystal display deviceaccording to claim 20, wherein liquid crystal molecules in said liquidcrystal layer align tilted against said first or second substrate. 29.The liquid crystal display device according to claim 20, wherein liquidcrystal molecules in said liquid crystal layer align twisted againstsaid first or second substrate.
 30. The liquid crystal display deviceaccording to claim 20, wherein liquid crystal molecules in said liquidcrystal layer align homogeneous against one substrate of said first andsecond substrates and align homeotropic against the other substrate. 31.The liquid crystal display device according to claim 20, wherein saidfuranose polymer comprises photo-sensitive part or non-photo-sensitivepart.
 32. The liquid crystal display device according to claim 31,wherein said photo-sensitive part is selected from the group consistingof cinnamoyl deriatives.
 33. The liquid crystal display device accordingto claim 32, wherein said cinnamoyl derivative includes hydrogen,fluorine, chlorine, cyano, trifluoromethyl, trifluoromethoxy,C_(n)H_(2n+1), OC_(n)H_(2n+1), phenyl, or C₆H₄OC_(n)H_(2n+1), (n is 1 to10).
 34. The liquid crystal display device according to claim 31,wherein said non-photo-sensitive part is selected from the groupconsisting of ester derivatives.
 35. The liquid crystal display deviceaccording to claim 34, wherein said ester derivatives is

 and n is 1 to 10.